The present invention relates to a sewing machine capable of effecting various improved functions by replaceably connecting one of a plurality of operating panels having functional keys.
Some of the conventional sewing machines have basic functions such as normal sewing and reverse sewing as basically required by a sewing machine, and further have additional functions such as start/end backtack sewing, continuous backtack sewing, stitch number sewing, pocket sewing and label attachment sewing.
However, some users do not require such additional functions, and some users require some but not all of the additional functions various requirements of the users can be met by providing a single type of sewing machine having all of the additional functions. According to this concept, however, some users are obliged to buy unnecessary functions, and the operation of the sewing machine is rendered complicated. To cope with this problem, a maker must produce various kinds of sewing machines to meet various requirements of all the users, causing a reduction of productivity in mass production.
Some measures for solving the above problem are disclosed in U.S. Pat. No. 4,052,946. This prior art sewing machine includes a machine body commonly having the basic functions, and also includes various kinds of control packages, one of which is selectively connected to the machine body, thus attaining the basic functions and various kinds of additional functions. In this prior art, a single type of the machine body is commonly utilized. However, each of the control packages includes an electronic circuit for controlling a sewing machine driving motor or the like, software for operating the electronic circuit and an operating panel for selecting various control modes. Accordingly, it is necessary to prepare a plurality of electronic circuitry, software and operating panels in correspondence with the number of control packages, causing an increased cost and a reduction of productivity in mass production.
Some measures for solving this problem are disclosed in Japanese Utility Model Publication No. 62-11578 (corresponding to Japanese Utility Model Laid-Open Publication No. 57-64280). This prior art sewing machine includes a common machine body, a common electronic circuit and common software for controlling the sewing operation, and also includes plural kinds of operating panels selectively connected to the machine body. The machine body includes selector switches corresponding to the operating panels, and the selector switches are manually selected according to the user's selection. In this prior art, most of the parts are commonly utilized. However, unless any one of the operating panels is attached to the machine body, the sewing machine cannot be operated. Thus, this prior art has yet some problems from the viewpoints of operability and cost.
Further, since the users must select the selector switches in the machine body according to the operating panel selected, there is a possibility that the users will erroneously select the switches or will not select the switches, causing improper operation based on the operating panel selected.